Planter (farm implement)
Like a grain drill a planter is an agricultural farm implement towed behind a tractor, used for sowing crops through a field. It is connected to the tractor with a draw-bar, or a three-point hitch. Planters lay the seeds down in precise manner along rows. Seeds are distributed through devices called row units. The row units are spaced evenly along the planter. Planters vary greatly in size, from 1 row to 48, with the biggest in the world being the 48-row John Deere DB120. The space between the row units also vary greatly. The most common row spacing in the United States today is 30 inches.
On smaller and older planters, a marker extends out to the side half the width of the planter and creates a line in the field where the tractor should be centered for the next pass. The marker is usually a single disc harrow disc on a rod on each side of the planter. On larger and more modern planters, GPS navigation and auto-steer systems for the tractor are often used, eliminating the need for the marker. Some precision farming equipment such as Case IH AFS uses GPS/RKS and computer-controlled planter to sow seeds to precise position accurate within 2 cm. In an irregularly shaped field, the precision farming equipment will automatically hold the seed release over area already sewn when the tractor has to run overlapping pattern to avoid obstacles such as trees.
Older planters commonly have a seed bin for each row and a fertilizer bin for two or more rows. In each seed bin plates are installed with a certain number of teeth and tooth spacing according to the type of seed to be sown and the rate at which the seeds are to be sown. The tooth size (actually the size of the space between the teeth) is just big enough to allow one seed in at a time but not big enough for two. Modern planters often have a large bin for seeds that are distributed to each row known as central commodity systems.
There are different types of planters available with the main difference being mechanical driven vs hydraulic/electrical driven. In a mechanical drive system the unit works by a small suspended tire being driven by another which is in contact with the ground (driven) tire. As the operator lowers the planter the two tires make contact and the planter is engaged. When the driven wheel begins to turn it then turns a series of gears that determine the population of the seed produced. The gears can be changed by the operator in order to change the planting population. A hydraulic driven system came about to correct the shortfalls of the ground driven system. Hydraulic driven systems allow the operator to change population on the go, as well as allowing the computer controller to follow a prepared prescription for a individual field. The system also allowed for plant populations to be infinite in that mechanical gears systems are limited to set number of population settings and gears available from manufactures. In 2014 John Deere introduced the ExactEmerge row unit which introduced high-speed planting. Precision Planting (later purchased by John Deere from Monsanto) followed suit and released the vDrive system. These system were unique, not that they electrical, but that they allowed an operator to double their speed when planting. Other manufactures had already developed an electrical planter, but lacked these additional improvements. Traditionally, an operator would plant at about 4.5-5.5 mph for optimal performance, however, with the advent of these systems electrical motors match the speed of the tractor and "dead-drop" the seed in the trench using either a belt or brush-belt which cause the forward momentum of the planter to be offset by the rearward momentum of the seed. Older systems would instead drop the seed through a tube after the meter rather than place is in the seed trench directly.
- "John Deere launches high-speed planter". farmindustrynews.com. Retrieved 2016-07-03.